Experimental studies on the stem cell concept of liver regeneration. I

There are increasing references for the existence of a hepatic stem or progenitor cell system as well as its participation in the physiological as well as reparative regeneration of the liver and in carcinogenesis. For the physiological regeneration the existence of a dynamic "cell-renewal" system finds increasing consideration and in the "streaming liver concept" (Zajicek et al. 1985) its functional expression. This concept is still under discussion. The present paper tries to check this animal-experimentally (Wistar rats) under use of two different thymidine analogues (3H-thymidine and Bromodeoxyuridine). In different time intervals after labelling (1 h, 14, 30, 60, 90, 120 d) a shift of the labelling bias or a migration of the hepatocytes in the liver acinus (Rapaport) in portovenous direction could be shown. The average migration speed is 0.575 microm or 0.0315 cell positions per day, the cell production rate is one in 31.5 days. The present paper results support the inclusion of a stem or progenitor cell system into the physiological regeneration of the liver and allow the classification into the "streaming liver concept" (Zajicek et al. 1985).